In cloud computing service, object storage service is a very important basic service. In the object storage service, data is written into a user's storage area as an object. The user can write, read and delete objects in that storage area.
In the existing object storage system, the maximum supported size of a single piece of object data is 5 T. When the object data is stored in the existing object storage system, the object data is generally divided into slices for storage. The relation between the object data and the slices is maintained by metadata.
In general, user operations on the object data include a copying operation and a deletion operation.
With regard to the deletion operation, existing solutions can be divided into two types:
1. direct deletion: data slices and metadata related to an object are directly deleted after the operation to delete the object is initiated by a user;
2. garbage collection: the physical space for an object is not released until a periodic conventional garbage scanning is performed rather than being released immediately during the deletion.
With regard to the copying operation, existing solutions use direct copying.
With regard to the existing direct copying operation and the direct deletion operation, the processing logic is complex, and failure occurs easily. In particular, when the object data is big, hundreds of thousands of slices may be involved in the copying/deletion operation. If abnormality or failure occurs during the processing, it not only possibly leads to the creation of garbage or incomplete data, but also easily leads to the inconsistency of metadata. In addition, when the object data is big, the process time of the copying/deletion operation is long, leading to a noticeable stress on the object storage system. If multiple users simultaneously initiate a large number of copying/deletion operations, causing sudden increase in the system load is caused, corresponding operations may even cease to be executed.
The main disadvantage of the garbage collection solution in the existing deletion operation is the waste of the storage space.